The present invention provides potatoes having a tuber yield of potatoes per plant higher than that of non-transformed potatoes cultivated under the same conditions, wherein a gene encoding DNA linking protein belonging to Dof family is introduced in the potatoes. The present invention also provides a method for producing potatoes having a tuber yield of potatoes per plant body higher than that of non-transformed potatoes cultivated under the same conditions, comprising introducing a gene encoding a DNA linking protein belonging to Dof family into the potatoes, and expressing said gene in the potatoes.